Vehicles such as snowmobiles have very active front end suspensions, at the end of which there is a unit such as a ski which is to be steered. It is common practice to steer the ski by turning some portion of the suspension system. Over a period of time wear can be expected to occur and a considerable amount of play both in the suspension and in the steering linkage results. Snowmobiles are subjected to very hard usage, and looseness or play in the suspension or steering mechanism is undesirable.
It is an object of this invention to provide a steering system which can overcome many of the effects of the prior art. For example, prior art strut-type steering ski suspension assemblies have been constructed so that a movable tube or strut directly supports the steering ski and is supported slidably in both the rotational and vertical directions with respect to the chassis of the snowmobile. In order to transmit the steering force from the steering mechanism to this movable tube, a steering arm aligned with the axis of rotation of the movable tube engages directly with the movable tube, slidably on the vertical direction but fixedly in the rotational direction. Such arrangements are shown in U.S. Pat. Nos. 3,931,862 and 3,977,485. After a period of use, undesirable slackness and play results between the steering arm and the movable tube.
Another objection to the prior art is that the movable tube is subjected to torsional force when the steering force is applied. This over a period of time can be deleterious to the movable tube and to its supporting mechanisms.
Yet another objection to the prior art is that the sliding surface of the movable tube, which should be kept as smooth and clean as possible in order to make a fluid sealing contact is exposed to and can be damaged by brushes or twigs during running operations.
Yet another problem in the prior art is the likelihood that the steering mechanism will collide against the steering ski and the chassis if a linkage is employed to transmit the steering force.
It is an object of this invention to overcome the foregoing problems of the prior art.